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Interface charging effects in ferroelectric Zn O – B a T i O 3 field‐effect transistor heterostructures
Author(s) -
Schwinkendorf Peter,
Lorenz Michael,
Hochmuth Holger,
Zhang Zhipeng,
Grundmann Marius
Publication year - 2014
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201330171
Subject(s) - materials science , transistor , ferroelectricity , optoelectronics , voltage , field effect transistor , gate voltage , heterojunction , electrical engineering , dielectric , engineering
Ferroelectric field‐effect transistors (FeFETs) with n‐type ZnO channel and BaTiO 3 gate oxide show an unexpected reversed switching behavior in terms of the polarity of the gate voltage. The device's source–drain current is reduced after applying an external gate voltage pulse which polarizes the BaTiO 3 such that the device is meant to be in the on‐state. Subsequent switching to the off‐state with the opposite voltage does not influence the source–drain current. Furthermore, repeated switching cycles with increasing voltages result in a shift of the onset gate voltage in the transfer characteristics of the FeFETs. The observed switching behavior is explained by electron trapping at the ZnO/BaTiO 3 interface. In addition the charge accumulation and time, temperature and illumination dependent discharging effects are demonstrated. From current–voltage measurements we derive the trapped electron sheet density in dependence of the gate voltage. The interface charge density is in the order of 1 C m −2 .